'use strict'

const setWatermark = (str: any) => {
    const id = '1.23452384164.123412416'

    if (document.getElementById(id) !== null) {
        document.body.removeChild(document.getElementById(id) as any)
    }

    // 建立一个画布
    const can = document.createElement('canvas')
    // 设置画布的长宽
    can.width = 250
    can.height = 120

    const cans: any = can.getContext('2d')
    // 旋转角度
    cans.rotate((-15 * Math.PI) / 150)
    cans.font = '18px Vedana'
    // 设置填充绘画的颜色、渐变或者模式
    cans.fillStyle = 'rgba(200, 200, 200, 0.05)'
    // 设置文本内容的当前对齐方式
    cans.textAlign = 'left'
    // 设置在绘制文本时使用的当前文本基线
    cans.textBaseline = 'Middle'
    // 在画布上绘制填色的文本（输出的文本，开始绘制文本的X坐标位置，开始绘制文本的Y坐标位置）
    cans.fillText(str, can.width / 8, can.height / 2)

    const div = document.createElement('div')
    div.id = id
    div.style.pointerEvents = 'none'
    div.style.top = '35px'
    div.style.left = '0px'
    div.style.position = 'fixed'
    div.style.zIndex = '100000'
    div.style.width = `${document.documentElement.clientWidth}px`
    div.style.height = `${document.documentElement.clientHeight}px`
    div.style.background =
             `url(${can.toDataURL('image/png')}) left top repeat`
    document.body.appendChild(div)
    return id
}
const watermark = {
    set: (str: any) => {
        let id = setWatermark(str)
        setInterval(() => {
            if (document.getElementById(id) === null) {
                id = setWatermark(str)
            }
        }, 500)
        window.onresize = () => {
            setWatermark(str)
        }
    }
}
export default watermark
